Here is a short but cool and interesting article about an add-on to an application called "IP over Social Network" which I believe allows you to see IPs of people in your social network, but this new add-on is called the 'Graphical Topology' view. This view allows you to check out active nodes in your facebook network in a cool social network graphical node based network way.

Oh, very interesting. It seems that this program creates your social network based on how often you link with another IP address, hopefully in return a friend of yours. It eliminates any nodes you have not being in contact for awhile. This is interesting in that say facebook looks at the number of friends you are linked, but do you stay in contact with that many friends anyways? This allows us to see which friends you are in contact with the most, showing which friends you share the strong bonds with, thus showing clusters within the social network. However, tracking IP address of facebook users can be hard since, a person might not be using the same computer, or many people using the same computer. Say you are friends with 3 siblings. They share one computer. All of them have facebook, all of them are friends with you. IP tracking would only track one of these friends, while the other two would kind of be ignored.